Flexible-shaft bench grinder



A. B. BA'cHMANN 1111111151111 SHAFT BENCH 611111111111 miga nec. 2a. 1922 Mr-ch A z ,19211.

Patented 1 iLUNfITED *TAT-ES Y www' PATENT- A OFI-1611;

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CAI: ENGING CORPORATION, QF. BROOKLYN, NEW YORK,1'L.OBPOALTIOH -snnrr Bienen earn-nm Application led Deeexnber 28, 1922. Serial'lo. 609,870.

' To all whom 'itV may concern:

Be it known that I, A twlN a citizen of the United States, and'residerit of Brooklyn,4 county of Kings, and State oi New `York, have invented certain new and useful improvements Bench Grinders, of which' the following is a specification. My invention relates more particularly to a portable benchV grinder, in which a jack shaft and pulley is utilized in connection with a high speed motor, and means is pro` vided for adjusting the jack pulley, relative to the motor pulley, fortightening the belt.

In bench grinders of this character, a exible shat is vpreferably adapted to be operated by the jack pulley, the flexible shaft operating aj inding wheel which may be supported an ap lied to the work by means ofa suitable han e; The motor is preferablyan electric. motor of the usual enclosed A type and may be supported in a yoke or'Y- fork to permit adjustment thereof in a ver-v tical plane andthe fork is preferably ro-. tatably supported' in a pedestal forming the base of the machne',thereby providing for I horizontal adjustment.

lt will be understod that in' grinding Vmaf chlnes of this character, small grinding wheels are nusually used and they are required to4 be operated at highl speed. The

lid

motor used mayfbeof the vhigh speed type, nevertheless, itis frequently desirable to run Athe grinding wheel at even higher speed than the motor, andgfor this pur ose, an intermediate or jack pulley .is pre erablyV employed, the latter and thehmotor pulley being stepped orcone pulleys.

When a jack pulley of -this'character is employed and r uired to or crate' atA high i speed, it is articu arly'des'ira le that means be provide' for accurately adjusting the tension on the belt between the motor pulley kand the :jack pulley. Hence, one object of m improved invention is to'provdenieans w iich mayfbe'employed foraceurately and efiectivelytightening the belt and maintain'-k ing the necessary tension. 4

view ofthecfact that thpegack pulley is o erating at very high sp it 1s de 'sira le to; provide abelt guard and another ,Adr

.gleiect of my improvement is to utilize thet ard, cooperating withy the jack pulley,

" on e one hand, for supporting the 'end of B. BAGANN.

in Flexible-Shaft f 'the flexible shaft nd es th-other for hen- .5.5

ing the"jaclr shaft and pulley in adjusted position, or rather preventing accidental displacement or movement of the jack shaft after an adiustment has been made.

Mechanisms for carrying out these and .other object of my improvement are more particularly shown in the accompan. ing drawings, `which represent one form o my improved flexible shaft bench grinder. in the drawings, Fig. l shows the bench grinder in side elevation, with the jack shaft and parts associated therewith partially' in section; Fig. '2 represents apartial verticalv transverse section substantially on the line 2 2 of Fig. 1, showingsJ section through the swivel support and the worm .and gear ad'usting means for tensioning the belt.

eferring tothe drawings, 1 is the base j or pedestal and column for supporting the motor and attached parts, and is preferably provided with a tubular bore at 2, in whic a shaft or rod 3 is rotatabl mounted; the rod 3 bein secured to a yo e or fork 4 by means of t e in 5, thereby providing means for horizonta rotation ofV the fork on the sup orting column 1.` Within the yoke or for 4, the electric motor 6 is'adapted to besupported for movement in a vertical plane.' For this purpose, the motor casing lsprovided with ears or bosses 7 arid 8, "from which, project studs 9 and 10, which pass thrugh holes in-the upperl ends of the arms of the fork or yoke 4,-substantially as 'shown in Fi 2 of' the drawings. Suitable means may4 provided for preventingy the rotationl of the motor on its pivotal supports 9--10 or for clampin the same in any adjusted position and orthis pu stud 10 1s here. shown as pro'vl with av wing nut 11 which, it will be seen, may

ose, the ed be utilized for clamping the motor to' the fork 4 in any adjusted position.-

'The jelectricmotor '6 is provided with the usual shaft 12 to which the stepped or cone ulleys 13 are secured in the usual manner.

The 'pulley 13 cooperates, in the' present instance, with corrpionding stepped orcone 14, moun on a jack "shaft- 15,.`a`s

The' )ack Sima wie prefer-abi .olf-set eecentrically of and forms a cran exte ding pivotal 16,Y and-rotatably -rom one end` of a crank or" mounted `a tubular boss 17, formed integrally with lor as art of a bracket 18, secure to the top o thev motor casing by suitable bolts 18, as indicated in Fig. 1. The

' bearing boss 17 lsvpref'erably formed so that it readily provides a handle for carrying or moving the portable grinder e uipment.

Obviously, with a belt 19 tween the `motor pulleys 13 and thev -corresponding jack pulley 14,` it becomes desirable to accurately adjust the tension on the belt. This may be accomplished in various ways, but preferably the eccentrically mounted. stud shaft 15 is adapted to be revolved about the axis of that part 16, of the combined shafts, which serves as the pivotal support for the stud shaft. For this purpose a worm gear 2() is preferably secured to the pivotal shaft 1G and a worm 21 is rotatably sup orted in the bracket 18, transversely of 't e crank shaft 16 and cooperates with the worm gear 20, so that by rotation of the worm, the position of the crank pin or stud shaft 15, relative to the axis of the motor 6 and the shaft l2 thereof, may be varied. The worm 21 is provided with an arbor extension 22, to which a knurled head 23 is secured, as indicated in Fig. 2 of the drawings, whereby the worm may be readily turned by hand for adjusting the tensionv of the belt.

The jack pulley 14 is preferably mounted upon the crank vpin or stud shaft 15 by ball bearings, indicated at 24, the pulley being held 1n place on the stud shaft by a nut 25 or other suitable means. The outer end of the stud shaft 15 and the ball bearings of the pulley are preferably covered by a cap 26 which may be secured tothe outer flange of the pulley 14 by suitable screws 27, as indicated in Fig. 1 of the drawings. The cap 26 is preferably provided with a boss 28, which is bored out at 29, to receive the shank end 30 of a flexible shaft,

the latter being provided with the ordinary flexible tube or enclosing armour 31. The shank 30 is preferably flattened and cooperates .with a transverse pin 32, so that the flexible shaft may be caused to rotate withl the jack pulleys 14. The shank 30 of the fiexible'shaft preferably extends through a thimble or collar 33, .to which the tubej or armour 31 of the flexible shaft is secured by suitable thread and lock nut 34, as indicated in Fig. 1 of the drawings. A suitable bracket may be provided for supporting the fhimble 33, and the end 30 ofthe flexible shaft in operative connection within the socket 29 ofthe jack pulley 14, and preferably, this-bracket comprises a belt guard 35 provided with two horizontal ribs 36 and a medial rib connected with a plate 37, which is bored out at 38 and loosely mounted upon the inner, supported end of thestud shaft 15, as will be seen in Fig. 1 of thedrawings. The upper end of the. guard plate 37 is `the jack shaft and pulley against an dental displacement 0r from any furt er adretraso? provided with a bolt 39 extending through a slot 40 in an upwardly-extending arm of the bracket 18, as more particularly shown-in Figs. 1 and 2of the drawings. The bolt 39 is preferably provided with a wing nut 41, whereby the beltguard may be clamped .to

" the bracketx 18. In view of the fact that the beltguardplate 37 surrounds the stud shaft 15, 1t will. be understood that clamping of the belt guard to the bracket 18 clamps the.

studshaft .against rotative movement for adjustment purposesA in either direction.v

Therefore, when the wing nut 41 `istightened to. clamp the belt guardplate to the bracket 18, the worm 21 cannotbe turned effectively` to cause a displacement or adjustment of the position of' the *study shaft 15.

Obviously, the jack pulleys 14 may be connected to operate a grinding wheel or tool in any suitable manner, but preferably it is connected with 'a suitable flexible shaft,

passing through the tubing or armour' 31,-

thc outer end of which'A is connected at 42,

with a shaft 43 rotating on ball bearings 44,v

in a handle 45, and a suitable chuck 46 is attached to or formed upon the shaft 43, in which the` arbor 47 of a suitable grinding wheel 48 may be secured, nsubstantially as indicated in Fig. 1 of the drawings.

,The operation of my improved flexible shaft bench grinder is simple, for it will be understood that the pivot support at 3 permits the motor to be 'readily rotated in a horizontal plane and the pivotal mounting of the motor inthe fork 4 allows vertical adjustment of the position of the motor and the latter may be clamped in any desired position by the wing nut 1l.

When it is desired to adjust the tension of the belt 19 the crank pin or jack shaft 15 may be revolved about the axis of the crank shaft 16, to which it is secured eccentrically.

This rotation of the stud shaft is accomf which Awhen rotated, rotates the worm l21 and hence the worm gear20, the latter being secured to the pivotal shaft 16. As previously explained, however, the belt guard plate 37 is mounted upon the. stud `shaft l5 and clamped to the bracket 18, by the wing nut 41 and, therefore, before attempting to Shift the position of the stud shaft 15, the wing nut 41 should be loosened. After adjustment of the shaft l5 and jack pulley 14 to tighten the belt 19 the belt guard plate 37 may again be 'clamped to the bracket 18 by tightening the wing nut 41, thus securing accijustment, by means of the knurled head 23. In carrying out my improvement, it will be understood that the form shown and de scribed represents the preferred form ,and obviously, various modifications in the specific details of construction and in the adapmaybe made without departing froml the ably rotating said crank spirit and scope of the invention.

1. Inl a portable grinding machine,'pro vided with a short belt drive adapted for swiveling movement with the motor, the combination with a motor provided with a shaft and pulley, of a bracket mounted upon the. motor, a-crank shaft rotatably mounted in said bracket and rovided with a crank pin forming a jack shaft, a jack pulley rotatably mountedupon said crank pin and means for rotating saidcrank shaft, in said bracket for varying the distance between the jack pulley and the pulley of Said motor. g 2. In a lportable grinding machine provided with ashort belt drive adapted for swiveling movementwith the motor, the combination with a motor provided with a shaft and pulley, of a bracket secured to said motor,a tubular bearing boss inte A al with said bracket and extending paralle to the axis of said motor, .a crank shaft rotatably mounted in said tubular bearing and provided at one end with `a crank pin .carrying a jack pulley, and means foriadjustshaft and pin to vary the distance of said jack pulley from the pulley of said motor.

3. In a portable grinding machine, provided with a short belt drive adapted for swiveling. movement with the motor, the com- Worm gear carried by said crank s aft and4 tating said crank shaft and bination with a motor provided with a shaft 4 and pulley, of a bracket secured to said motor, a crank shaft extending parallel to the axis of said motor, and rotata ly m'ounted in said bracket, a crank lpin rejecting from the end of said crank sha a jac pulley rotatably mounted on said crank pin for cooperationl with the motor ulley, a

a worm cooperating with saidvgear for ropin to vary the distance between said pulleys.

4. In a portable grinding machine, provided with a 'short belt. drive adapted for swiveling movement with the motor the' combination with a motoigprovided with a shaftV and pulley, of a-bracket mounted on said motor, a crank shaft rotatably mounted in said bracket and provided with a crank pin, a jack pulley rotatably mounted-on said Y crank pin, means' for rotatin shaft and pin for moving sai jack pulley to vary its distaiice'from the motor pulley, a belt guard cooperating with said jack pull ley and adapted to be supported by said bracket, and means for clampin said guard to the bracket and simultaneous y clamping.

said crank said crank shaft so as to hold said jack pul- I ley inadjusted osition. v

5. In a porta le rinding machine, provided with a short elt drive adapted for swiveling ',movement with -the motor, the combination with a motor provided with a shaft and pulley, of' a jack pulley rotatably supported on a crank-pin, a crank shaft sup.- porting said crank pinfor rotative movement toward and from the shaft of Said motor to vary the distance between said pulleys, a belt guard cooperating with said jack pulleya flexible shaft having one endV supported y said belt guard, and means for operatively connecting said llexible shaft with said jack pulley to be driven thereby.

6. In a portable rinding machine, provided with a short elt drive adapted for swiveling movement. with -tlie n motor, the

combination with a supportinglcolumn, of a yoke mounted to swivel horizontally on said column, a motor mounted in said yoke, for Swingin' movement in a vertical plane, means for c amping the motor to said yoke in its adjusted position, a flexible shaft adapted to be driven by a ulley on. the motor, a jack pulley to whic said iexible shaft is connected, a bracket on the motor for supporting said jack pulley, a rotatable member carrying a crank pin on which said jack ulley is mounted, means mounted on said racket for rotating said member and the crank pin for adjusting said 'ack pul-.

ley toward and from the `pulley of t e motor, and means for holding saidV member in ad justed position.

fALWIN B.;BACHMANN. 

